I think the bank teller's systems and processes are deterministic, but the teller itself is not. They could even rob the bank, if they wanted to. They could shoot the customers. They don't, generally, but they can.

I think, if we can efficiently capture a way to "make" LLMs conform to a set of processes, you can cut out the app and just let the LLM do it. I don't think this makes any sense for maybe the next decade, but perhaps at some point it will. And, in such time, software engineering will no longer exist.